Deprotection of p-nitrobenzyl esters and valyl carbamates in carbapenem CL 192,276 produced the active compound OCA-983 in excellent yields. Straight chain alkanols such as 1-butanol, 1-pentanol and 1-hexanol in water at certain ratios were effective solvent systems. Alkyl acetates in water also resulted in simultaneous deprotection of PNB and PNZ side-chains albeit at slower rates. The deprotected carbapenem was isolated in excellent yield and purity after removal of the aqueous media. This procedure is applicable to sensitive compounds that are soluable in water without the need to use a buffer and allows for ease of isolation from the aqueous phase.
Keywords: ethyl acetate-H2O, n-butanol-H2O, biphasic media, PNB/PNZ side-chains, deprotection, carbapenems, OCA-983
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